


I'm Full of Dumb Ideas, and This Is One of Them

by Snapped_Writing_Quill



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Accidental Voyeurism, Explicit Sexual Content, Implied/Referenced Character Death, M/M, Mutual Pining, Non-Consensual Voyeurism, don't read if you haven't gotten very far in the game
Language: English
Status: Completed
Published: 2019-10-05
Updated: 2019-10-05
Packaged: 2020-11-24 02:57:20
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,864
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20900525
Author URL: https://archiveofourown.org/users/Snapped_Writing_Quill/pseuds/Snapped_Writing_Quill
Summary: Byleth doesn't think his plan through, and Seteth needs to relieve some stress every now and then. A mutual pining fic, with things currently left unsaid between them.AKA: Byleth winds up accidentally watching Seteth having a good time. Seteth isn't aware that he's watching, so here's a warning if that squicks you out (it's also in the tags).





	I'm Full of Dumb Ideas, and This Is One of Them

**Author's Note:**

> This is my first-ever fanfic that I have had the nerve to post! Constructive criticism is appreciated (as are general comments).
> 
> My Tumblr and Twitter is Snapped_Writing_Quill if anyone wants to follow me there.

Byleth started looking for his father's journal the moment he notices it's missing from Jeralt's office.

  
It had only been three weeks since he had started to read it, but since then, he had gotten caught up in the pursuit of his killer, and things had happened one after the other since the last time he had gotten to pick up the book.  
Unfortunately for him, it seems that someone else had already gone through the dusty bookshelves before the professor had a chance to retrieve it. As things were, he had no idea where it could be- he had searched the entire office, his personal quarters, and even went so far as to ask Leonie to see if she had taken it, which she vehemently denied.  
Jeralt's journal was nowhere to be found.

One week later, as luck would have it, as Byleth walked to Hanneman's office for a meeting, he overheard an argument coming from Rhea's office.  
"-I read the captain's journal, Rhea. What did you do to-?" He recognized the voice as belonging to Seteth.

  
_So that's where the journal had gone. Of course he has it- their offices were right across from each other.  
_

  
Although he was a interested in the argument, Byleth continued to walk; if the tones of their voices were anything to go by, it sounded like the argument would be a long one.

Casually diverting off of his original course to the crest scholar's room, Byleth walked into Seteth's office, quickly scanning the area to see if there was any trace of the battered journal among the stacks of papers and tomes on the large desk.

The book was nowhere to be found.

_ Where else would the advisor keep it?_

Seteth spent most of his days in his office, or Rhea's.

It seemed unlikely that Seteth would have taken the diary with him to confront Rhea since the journal was interesting to him, and it was more likely that the advisor might be hiding the book in a safer location until he was done with it.  
It was annoying that the book was moved, but Byleth was oddly touched that the taller man considered the journal to be an artifact of interest, and overall, seemed to be taking measures to ensure that it didn't fall into the general public's hands.

  
It seemed like something the reserved man would do, considering his actions of late.

While Seteth hadn't sat and murmured words of comfort to Byleth after his father's death, throughout the following weeks the typically reserved man had been going out of his way to do small things for the young professor: bringing hot cups of chamomile tea to Byleth while he was shut up his room, making sure that his students' classes ran smoothly without their normal teacher present, and Byleth knew that Seteth that had been placing fresh flowers on his parents' grave every morning.  
Although Byleth never saw Seteth place the flowers, gossip spreads quickly at the monastery and the show of kindness from the advisor spurred rumors that quickly got back to Byleth's ears, shut-in or not.  
There were only a few people at Garreg Mach that had a penchant for finding forget-me-nots, and the whispers definitely mentioned a tall man with dark green hair praying at the Eisner grave site. 

Byleth realized that he was still standing in Seteth's office, and mentally shook himself to bring his thoughts to the present.

_If the journal's not in here, and it's not with Seteth, where could it be?_

There aren't many places to keep a book without someone noticing, not with students everywhere.

_Maybe in his room?_

It was worth a try to look there, anyway.

Taking a deep breath to ground himself, Byleth exited Seteth's office, and walked quickly down the corridor leading to the third floor, towards the advisor's and archbishop's quarters.  
Making sure to listen as he passed the entrance leading to Rhea's office, the light-haired man heard Seteth and the archbishop, still arguing.

_Well, they seem occupied for now. No time to investigate like the present._

  
With one last glance around to make sure he wasn't noticed, Byleth quickly climbed the stairwell up to the top floor. Once he reached the landing, he spotted the second, smaller room at the end of the hallway, just beyond a large set of wooden doors.

  
With a few quick strides, he reached the room and ushered himself inside, quietly closing the door behind him. Pausing a moment to listen until he was satisfied that he wasn't heard, Byleth turned around to take in the room's layout.

Seteth's room was not lavish, like he had expected. It was simple, but had a subtle touch of elegance- a dark wooden bed was adorned with clean white sheets, and on separate sides, a single nightstand and simple chair made of the same dark wood was placed next to it. Along one wall a large, intricately-carved wardrobe with double doors stood, and in the corner was a small washbasin on a stand with a small white towel. The room was subtly well-made, tidy, and pristine, just like the man it belonged to.

Besides the quality of the wood used for the room furnishings, the other thing that stood out to Byleth was the single white lily in the vase on the nightstand- internally, Byleth had to wonder if it was the same flower he had given to Seteth on their last mission.

  
He had picked the lily because he thought it would contrast beautifully with the dark green color of Seteth's hair. Not that he mentioned that to him, of course- he had simply handed Seteth the flower in complete and total silence.  
What the advisor made of it was out of Byleth's hands- or so he told himself.

If he was being honest, there were a lot of things he found intriguing about Seteth: his stern but caring personality, the way he seamlessly rotated between using an axe and a lance in the heat of battle, how his strong hands hold his weapon as he follows through a thrust with an armor-piercing strike.  
The gentle, faraway look that he wears unconsciously when he sits on the pier, holding an old fishing rod in his hands.  
The bright excitement in his eyes when discussing everything from battalion tactics to the spiced flavor palette of certain teas.  
How he was both a holy man and harbinger of death, rolled into one stern but ultimately kind person.

It also doesn't hurt that he's good-looking, an observation that Byleth had been very determinedly trying to ignore, but the fact that the advisor skillfully rides a wyvern in battle doesn't exactly do Byleth's libido any favors.

From his position on the battlefield as a swordsman, Byleth can look up and see Seteth perched on his saddle every time they go out on missions, and although Byleth may be the savior of Fodlan, he's still just a man.

  
He's caught himself staring at the advisor's ass before, during their mission to the seaside where he had spent the better part of the three hour trip vainly trying not to get distracted by the way Seteth's hips rocked with each sway of his wyvern.

But he'd be damned if he was going to say anything about it- Seteth was a good man, and after he had revealed that they were at the grave site of his wife after the mission, Byleth guiltily tamped down any such thoughts of the devout man, and had been trying to keep them at bay since. 

Just because Seteth was being nice to him didn't give him leeway to ogle.

Byleth had to shake himself from his thoughts once more to focus on the task at hand. It would be best to hurry, before people start to notice he's gone- Hanneman already must be wondering where he had gone off to.

  
After a quick scan around the room, Byleth found the worn journal nestled in the nightstand drawer, partially wrapped in a heavy cloth to keep it from damage. As he started to pull the book out of the drawer, a small ceramic bottle that was hidden under the journal rolled forward with a noise that seemed deafening in the quiet room.  
While trying to take out the book and quietly set the bottle upright, Byleth heard Seteth's voice floating up from the bottom of the stairwell, speaking to someone.

Scrambling to hide, he placed the book back in the drawer, and pushed it closed.

If he left now, Seteth would see him in the corridor, and be naturally suspicious as to _why_ the professor was sneaking around the third floor-the advisor was an intelligent man, and it wouldn't take long for him to put two and two together.

The last thing Byleth wanted was to have the diary moved to yet another new and unknown location.

As Byleth frantically looked around for a hiding spot in the modest bedroom, he spotted the large wardrobe along the wall, easily within an accessible distance. He bolted for it and shoved himself inside, almost closing the door completely just as footsteps sounded outside the doorway.

The wardrobe door was slightly ajar, but Byleth didn't dare try to move the door again, lest it make noise and alert Seteth, who was walking through the doorway at that moment.

Byleth's stomach dropped as heard the definitive _click_ of Seteth locking the bedroom door behind him, effectively trapping him within the room.

_Damn his stupid ideas. Damn his own recklessness._

While Byleth mentally cursed himself for his actions, Seteth began pacing around the room, rubbing his temples. Letting out a long sigh, he paused his ministrations and walked over to study the clock on his wall, the tension from arguing with the Archbishop obvious in the tense way he carried himself.

After pondering the time for a few moments, Seteth seemed to have come to a decision, forcibly relaxing his stance and turning to walk towards the bed.

Byleth held his breath as the tall man walked past the wardrobe, lest her hear him. 

Seteth quickly took off his boots and unbuttoned his robes, shrugging them off to reveal a lean and muscular chest with a dusting of dark green hair leading down his torso. As the advisor turned to place his clothing on the back of the chair, Byleth caught sight of a happy trail that led down to a..._well_. Byleth hadn't imagined Seteth to be a _small_ man given his physique, but he was still surprised to see how well-endowed the man was. From what Byleth could see through the door's opening, a rosy, flushed head lead the way to a more dusky-colored, thick shaft, all of which was completed by a neatly-groomed hair an even darker shade of green.

_Oh come on, he's attractive, and big? Now that's just unfair._

Taking a deep, relaxing breath, Seteth paused next to the bed, catching the professor's attention as he took his circlet off and set it on the nightstand. Sitting down onto his mattress, the advisor sighed as he laid back onto the plush pillows that propped him up halfway, beginning to leisurely stroke his cock.

Occasionally grazing his fingers over the head, Seteth bit his lip to keep from making too much noise while he started to add a little more friction on the upstroke, teasing himself to full hardness as he pumped his length. The advisor groaned quietly, starting to work himself up, and stretched out a bit more to get comfortable, beginning to stroke in earnest. After a few more minutes of indulging in pleasure, he reached down into his nightstand drawer and took out the little bottle that had almost blown Byleth's cover.

_So that's what that was._

  
Seteth popped the cork off of the bottle, and poured a generous amount of oil onto his hand, spreading it across his skin to warm it up before rubbing an oil-slicked finger around his entrance, struggling to keep quiet as he breached himself.

Byleth would have never imagined himself in this scenario, not in a million years. Trapped in a wardrobe, watching the man you've been dancing around for the past year finger himself open and making the loveliest picture you've ever seen? It sounded like something you'd only read about in some of the more mature stories that Seteth would sometimes confiscate.

And yet, here he was, watching that fluffy, tousled green hair shift on the pillow as Seteth turned his head from side to side, worrying his lower lip between his teeth as he slowly added a second, then third finger, breathing more heavily as he worked himself up. The hand on his cock sped up, and Byleth could see how much Seteth was enjoying it as a large drop of precome leaked out of the slit and dribbled down his length, getting caught in Seteth's palm as it added to the glide of his motions.

  
He couldn't look away from the advisor, entranced by the sight of his pretty pink rim stretched around those fingers and his cock, now fully hard, bouncing along to the thrusts that he was making in and out of himself.

Byleth held his breath, and silently adjusted the pressure in his groin as he watched the gorgeous man ride his fingers with increasing desperation. The sight of Seteth mouthing silent words as he curled his fingers, stroking that sensitive spot inside of him again and again was...certainly having an effect.

Seteth moaned, softly, "B-Byleth, right there. Oh, _please,_ I'm going to come-_Oh__!_ _Ngh_..." The hand that had been pumping his cock moved up to muffle the noises from his mouth as he shuddered, coming on his hand and stomach, as he coated himself in pearly white fluid.

The professor sat motionless in the wardrobe, stunned- did Seteth just moan _his name_? He was sure of it-

Byleth's pants were uncomfortably tight, he was hard as a rock, and unable do anything about it. His vow to not get caught only marginally outweighed his desire to storm over to where Seteth was splayed out on the bed, yank open those gorgeous long legs of his, and pound into him right then and there.

At least he'll have memories of this moment to add to the ever-increasing collection of secret thoughts about Seteth that keep him warm on cold and lonely nights.

Now that he's personally seen Seteth finger himself open to the thought of him, though, it's going to be a _lot_ harder to focus on anything else when they train together.

Seteth removed his fingers from himself with a small groan and stood up a bit awkwardly, cupping his hand underneath himself, as he walked over to the washbasin and began to clean himself up. After he dried his body with the small hand towel, he combed through his fluffed-up green locks, hiding the fact that he had been thoroughly enjoying himself a just few moments before.

Covering up the fact that he had just imagined the former mercenary buried inside of him, clamping a hand over his mouth while Byleth bent over him and stuffed him full of cock.

Byleth had to take a deep breath to calm himself before he made any mistakes. Or outright _stupid_ decisions.

He waited, motionless, for a few more minutes as Seteth finished putting himself back together.

Now clean and dry, Seteth put his undergarments, tunic, boots, and circlet back on, once more becoming the picture-perfect image of a holy advisor.

Double-checking the time, Seteth gave himself one last look-over before he unlocked the door and hurried down the corridor, presumably to attend his next meeting.

Byleth breathed out a sigh of relief, and listened for a moment, making sure the advisor's footsteps sounded down the stairwell before opening the wardrobe door.

Now confidant that he was alone, the professor better adjusted his pants to relieve some of the pressure in his groin before walking over to the nightstand and pulling the diary out of the drawer.

He couldn't take it now since Seteth had just seen the diary in the drawer a few moments ago, and the man would know someone had been in his room after some point that day. After all, it would only take a few questions around the monastery to find out that Byleth hadn't met up with Hanneman that afternoon, and that would be pretty hard to explain away. 

Just taking the book would make things both easier and more difficult- on one hand, he would have the diary. However, Seteth would definitely find out that he had sneaked into his room, and then he'd _never_ hear the end of it. There was only a handful of people that knew that book existed, as far as he knew.

Sighing, he quickly browsed through another chapter and then gently set the journal back into its cloth wrapping. As he placed the book back into the drawer and closed it, he felt a small thrill go through him at the thought of sneaking back up to read another chapter.

As long as Seteth doesn't find him out.


End file.
